Electronic circuits occasionally undergo such a state that a power supply voltage exceeds or falls below an operating voltage range. Such electronic circuits often include components, which are sensitive to voltage excursions of the power supply, such as microprocessors (μP, MPU), microcontrollers (μC, MCU) or systems-on-chip (SoC). When the power supply voltage applied to an MPU, an MCU or an SoC deviates from an operating voltage range, the MPU, the MCU or the SoC may be in an unknown state, thus causing unpredictable behaviour.
Various approaches have been developed in the past to solve such a problem. One known approach includes using a low voltage detector in an electronic circuit. The low voltage detector incorporated in the electronic circuit senses or detects whether the power supply voltage falls below a predetermined threshold voltage, and then outputs a signal for resetting or halting at least the part(s) of the electronic circuit sensitive to power supply voltage excursions, thereby preventing that/those part(s) from malfunctioning.
Analogously, a high voltage detector may be used to protect electronic circuits from unknown states. The high voltage detector incorporated in the electronic circuit senses or detects whether the power supply voltage exceeds a predetermined threshold voltage, and then outputs a signal for resetting or halting at least the part(s) of the electronic circuit sensitive to power supply voltage excursions, thereby preventing that/those part(s) from malfunctioning.
In general, the high/low voltage detector always senses or detects the power supply voltage regardless of an operating state of the microcontroller.